A railway wagon generally comprises a wagon body, a bogie and a braking device, wherein the most commonly used bogie on the railway wagon is a two-axle cast steel three-piece bogie. As shown in FIG. 1, FIG. 1 is a structure view of the bogie of the prior art. The bogie comprises a bolster 11, two bogie side frames 12 and two wheel sets 13, wherein the ends of the wheel sets 13 are provided with an adapter 14. The bogie side frame 12 can be connected with the wheel sets 13 via the adapter 14. In order to improve the dynamic performance of a vehicle, a journal box rubber pad 15 is mounted between the bogie side frame 12 and the adapter 14. The journal box rubber pad 15 has the advantages that the elastic positioning between the wheel sets 13 and the side frames 12 can be obtained; the impulsive load between wheels and rails and the vibration of the vehicle can be reduced, and the dynamic performance of the vehicle can be improved.
FIG. 2 is a structural view of Embodiment 1 of a journal box rubber pad of the prior art. Refer to FIG. 2, the journal box rubber pad mainly comprises an upper wear liner 16, a lower wear liner 17 and a rubber layer 18 which is vulcanized and formed therein, wherein the upper and the lower wear liners are generally metal boards. The journal box rubber pad is generally in plane shape or in the shape of Chinese character “” when it is viewed from the side. Moreover, in order to adapt to railway electrification which is developed gradually currently, connection wires can be installed between the upper wear liner and the lower wear liner. Through the contact between the upper wear liner 16 and the bogie side frame as well as the contact between the lower wear liner 17 and the adapter, the journal box rubber pad can have conductive function, and the space between the bogie side frames and the wheel sets become a conductor. Therefore, the railway vehicles have conductive capacity by themselves, which prevents the potential difference among the vehicles, the ground and the rails from harming the vehicle operators standing on the ground. However, there are still certain problems of the journal box rubber pad installed with wires. That is, the upper and the lower wear liners are difficult to manufacture, which results in the following disadvantages that: the accuracy is low; the contacting states between the upper wear liner and the bogie side frames as well as that between the lower wear liner and the adapter are then poor; loads can not be spread effectively; the dynamic performance of the vehicles is getting worse; the upper and the lower wear liners made of metal are easy to produce abrasion; especially when the contact state is poor, the abrasion will become more serious.
FIG. 3 is the structural view of Embodiment 2 of a journal box rubber pad of the prior art. As shown in FIG. 3, in order to overcome the above defects of the journal box rubber pad and improve the dynamic performance of the vehicles, one thin rubber layer 19 can be vulcanized on the outer surfaces of the upper wear liner 16 and the lower wear liner 17, respectively. The overall shapes of the upper and the lower wear liners can be guaranteed by the thin rubber layer 19 and a vulcanization mould, which can decrease the manufacturing accuracy of the upper and the lower wear liners. In additions, as there is the thin rubber layer 19, the contact state between the journal box rubber pad and the bogie side frames as well as that between the journal box rubber pad and the adapters can be improved; the vertical distribution is even; bearings are stressed in equilibrium; the positioning between the journal box rubber pad and the side frames as well as that between the journal box rubber pad and the adapters become more sufficient, and there is not any abrasion between the upper and the lower wear liners.
However, the disadvantages of the journal box rubber pad of the structure shown in FIG. 3 are also obvious. That is, as there is the thin rubber layer 19, the electric conduction of the journal box rubber pad can not be realized according to connecting the upper board with the lower wear liners by wires; therefore, there may be potential difference between the vehicle and the ground as well as that between the vehicle and the rails, which may cause potential safety hazard to the vehicle operators standing on the ground.